Primed film comprising a polymeric substrate with copolymer layer thereon

Abstract

A primed film comprises a polymeric film substrate layer having an adherent layer comprising a copolymer comprising comonomers (a) 35 to 40 mole % alkyl acrylate, (b) 35 to 40 mole % alkyl methacrylate, (c) 10 to 15 mole % of a monomer containing a free carboxyl group, and (d) 15 to 20 mole % of an aromatic sulphonic acid and/or a salt thereof. The primed film can be used, for example, for producing metallised films, drafting films, photographic films and magnetic cards.

I claim: 
     
       1. A primed film comprising a polymeric film substrate layer having on at least one surface thereof an adherent layer comprising a copolymer comprising comonomers (a) 35 to 37.5 mole % alkyl acrylate, (b) 35 to 37.5 mole 5 alkyl methacrylate, (c) 10 to 15 mole % of a monomer containing a free carboxyl group, and (d) 15 to 20 mole % of an aromatic sulphonic acid and/or salt thereof, said adherent layer having a surface resistivity of less than 10.5 log ohm/square at 70% relative humidity and improved CAB lacquer or gelatin adhesion compared to the unprimed substrate. 
     
     
       2. A primed film according to claim 1 wherein comonomer (a) is ethyl acrylate, (b) is methyl methacrylate, (c) is itaconic acid and/or acrylic acid, and (d) is p-styrene sulphonic acid and/or a salt thereof. 
     
     
       3. A primed film according to either of claims 1 or 2 wherein the adherent layer is at least partially cross-linked. 
     
     
       4. A primed film according to claim 3 wherein the adherent layer comprises at least 10% by weight of a cross-linking agent. 
     
     
       5. A primed film according to claim 1 wherein the adherent layer comprises a particulate filler having a particle size of less than 5 μm and being present in an amount of up to 200% by weight of the copolymer. 
     
     
       6. A magnetic card which comprises a magnetic layer applied directly or indirectly over a first adherent layer of the primed film according to claim 1, and a graphics layer applied directly or indirectly over a second adherent layer of said primed film, said second adherent layer being applied to the surface of the polymeric film substrate opposite the magnetic layer. 
     
     
       7. A photographic file which comprises a light-sensitive photographic emulsion applied directly or indirectly over the remote surface of the polymeric film substrate of the primed film of claim 1. 
     
     
       8. A metallized film which comprises a metallic layer applied directly or indirectly over the adherent layer of the primed film of claim 1. 
     
     
       9. A drafting film which comprises a lacquer layer applied from an aqueous and/or organic solvent, directly or indirectly over the adherent layer of the primed film of claim 1. 
     
     
       10. A primed film according to claim 1 wherein the copolymer comprises ethyl acrylate, methyl methacrylate, itaconic acid and p-styrene sulphonic acid in the ratio of 37.5/37.5/10/15 mol %.